"An excellent source for the advanced undergraduate seeking to make the transition to higher mathematics. Future computer scientists and number theorists interested in applications will find this book a good foundation text." -- MAA Reviews"Ideal for a course in abstract algebra, providing students with a sound background in algebra, while teaching them many current-day uses of algebra in the real world. The reviewer was particularly impressed with the flow and depth provided for each application and found the discussions fascinating."--Libertas Mathematica"The whole book would be suitable as a text for a year-long course in algebra, or the first chapter by itself for a short course in number theory, or the first three chapters for a semester-long course in algebra. It is noteworthy for its inclusion of extensive historical material on breaking the Enigma code in World War II and the theorems used to accomplish this." -- SIAM Review